Singer slams the report that Houston, 46, suffered a "horrifying backstage collapse" as "ridiculous. It did not happen.

"It is ironic that at the same time that the Enquirer claims it is deserving of a Pulitzer for journalism [for breaking the John Edwards-Rielle Hunter affair story], the tabloid is continuously publishing stories comprised of brazen lies cobbled together from claims made from anonymous sources," Singer fumes.

Houston -- who has been open about her struggles with drugs in the past -- released her first album in seven years, I Look To You, to strong reviews last September. The six-time Grammy winner has sold more than 170 million singles, albums and videos worldwide.